Feasibility, Validity, and Reliability of the Italian Pediatric Quality of Life Inventory Multidimensional Fatigue Scale for Adults in Inpatients with Severe Obesity

Objective: This study was aimed to examine the feasibility, validity, and reliability of the Italian Pediatric Quality of Life Inventory Multidimensional Fatigue Scale (PedsQL™ MFS) for adult inpatients with severe obesity. Methods: 200 inpatients (81% females) with severe obesity (BMI ≥ 35 kg/m2) completed the PedsQL MFS (General Fatigue, Sleep/Rest Fatigue and Cognitive Fatigue domains), the Fatigue Severity Scale, and the Center for Epidemiologic Studies Depression Scale immediately after admission to a 3-week residential body weight reduction program. A randomized subsample of 48 patients re-completed the PedsQL MFS after 3 days. Results: Confirmatory factor analysis showed that a modified hierarchical model with two items moved from the Sleep/Rest Fatigue domain to the General Fatigue domain and a second-order latent factor best fitted the data. Internal consistency and test-retest reliabilities were acceptable to high in all scales, and small to high statistically significant correlations were found with all convergent measures, with the exception of BMI. Significant floor effects were found in two scales (Cognitive Fatigue and Sleep/Rest Fatigue). Conclusion: The Italian modified PedsQL MFS for adults showed to be a valid and reliable tool for the assessment of fatigue in inpatients with severe obesity. Future studies should assess its discriminant validity as well as its responsiveness to weight reduction.